Hitherto, as a technology relating to a three-way valve for flow rate control, there has already been proposed, for example, a three-way valve for flow rate control disclosed in Patent Literature 1.
In Patent Literature 1, provided is a constant-temperature maintaining device configured to control a temperature of an external heat load device through indirect heat exchange with heat-medium circulating liquid. The constant-temperature maintaining device includes a main unit and a sub unit. The main unit includes high-temperature heat-medium circulating-liquid generating means for generating a high-temperature heat-medium circulating liquid adjusted to a predetermined temperature, and low-temperature heat-medium circulating-liquid generating means for generating a low-temperature heat-medium circulating liquid adjusted to a predetermined temperature. The sub unit includes constant-temperature heat-medium circulating-liquid generating means for generating a heat-medium circulating liquid having a predetermined temperature by directly mixing the high-temperature heat-medium circulating liquid and the low-temperature heat-medium circulating liquid and controlling a flow rate ratio between the high-temperature heat-medium circulating liquid and the low-temperature heat-medium circulating liquid in accordance with a temperature of the external heat load device.
Patent Literature 1 also encompasses the constant-temperature heat-medium circulating-liquid generating means in a mode including a three-way valve, stirring-mixing-feeding means, and three-way-valve control means. The three-way valve includes an inflow port which allows inflow of the high-temperature heat-medium circulating liquid, an inflow port which allows inflow of the low-temperature heat-medium circulating liquid, an outflow port which allows outflow of the constant-temperature heat-medium circulating liquid, and a control valve configured to control the flow rate ratio between the high-temperature heat-medium circulating liquid and the low-temperature heat-medium circulating liquid. The stirring-mixing-feeding means is for stirring and mixing the constant-temperature heat-medium circulating liquid to feed the constant-temperature heat-medium circulating liquid. The three-way-valve control means is for controlling an opening degree of the control valve of the three-way valve in accordance with a temperature of the external heat load device.